Abstract: The influencing factors of multiplication coefficient, regeneration quality and rooting for adventitious shoots of pear dwarfing interstocks S2 , S5 and PDR54 were studied. The results showed that the regeneration ability of adventitious shoots was influenced by genotypes, media and plant growth regulators. MS
medium was more suitable for the proliferation of S2 , S5 and PDR54 than QL, WPM and AS media. The middle concentrations of 6-BA (2 - 3 mg·L ^{- 1} ) in combination with lower concentrations of IBA (0.1 - 0.2 mg·L ^{- 1} ) and GA₃ (1 - 2 mg·L^-1 ) could improve the proliferation of all the three interstocks, with proliferous index of shoots from 3.71 to 5.83. The best medium for S2 was MS + 3.0 mg·L ^{- 1} 6-BA + 0.2mg·L ^{- 1}IBA + 2.0 mg·L ^{- 1} GA₃ , while MS + 2.0 mg·L ^{- 1} 6-BA + 0.1 mg·L ^{- 1} IBA + 1.0 mg·L ^{- 1} GA₃ was the optimal for S5 and PDR54 proliferation in comparison of the comprehensive index of shoot quality, numbers and lengths. The regenerated shoots were rooted with a rooting percentage of 67% , 50% and 86% respectively for S2 , S5 and PDR54.

Key words: Pear, Dwarfing interstock, Rapid propagation